SystemVerilog: How to convert a binary vector to integer

Question

I have an 8-bit input A and also 3-bit input n. I want to shift A n times to left or right but this code doesn't seem to work (the output is x):

w = A << n;

But when i put an integer like 2 instead of n, the code works without problem. So how to convert n to an integer value so the shift operation can work without problem?

No amount of casting is going to make the output not an X. There must be more going on here. Can we see enough code to create something that could be simulated? — nguthrie, Apr 10 '17 at 19:05

score 0 · Answer 1 · answered Apr 09 '17 at 14:12

The shift operators always treat the expression on the RHS as unsigned. You also need to declare n as a signed variable, or cast to signed

bit signed [2:0] n;
assign w = (n >= 0) ? A << n : A>> -n;
bit [2:0] n;
assign w = (signed'(n) >= 0) ? A << n : A >> -n;

SystemVerilog: How to convert a binary vector to integer

1 Answers1